STUDIES ON COMPARATIVE DEVELOPMENT AND MANAGEMENT OF RICE WEEVIL (Sitophilus oryzae L.) ON DIFFERENT CEREALS
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Date
2022
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DRPCAU, PUSA
Abstract
The present investigation entitled “Studies on comparative development
and management of rice weevil (Sitophilus oryzae L.) on different cereals” was
carried out at Department of Entomology, Tirhut College of Agriculture, Dholi, Bihar
during 2021-22. The study focused on host preference and damage potential of rice
weevil, correlation between population build up and biochemical parameters of
different cereals and evaluation of the bio-efficacy of some entomopathogenic fungi
against rice weevil on different cereals. Among different cereals, wheat was found as
the most preferred host with 14.38 ± 0.48 numbers of weevils after 25 days of release
and F1 progeny of 329.13 ± 6.75 numbers. Maximum and minimum kernel damage
(%), weight loss (%) and consumed grain weight was recorded on wheat and ragi,
respectively. A negative and highly significant relation (r = -0.925**) between phenol
content and number of F1 progeny produced was observed. The LC50 value of
Beauveria bassiana after 72 hours of treatment varied from 1.778 g/kg of seeds (on
ragi) to 2.011 g/kg of seeds (on maize), whereas, that of Metarhizium anisopliae was
varied from 1.870 g/kg of seeds (on ragi) to 2.196 g/kg of seeds (on wheat).
Significant interaction was found between tested cereal grains and entomopathogenic
fungi, also between days after treatment and entomopathogenic fungi. It was observed
that Metarhizium anisolpliae in combination with diatomaceous earth and alone was
found most effective on rice, maize and barley as compared to Beauveria bassiana in
combination with diatomaceous earth and alone, respectively, whereas, opposite case
was observed on wheat, oat and ragi. Complete mortality of weevils (100 %) was
observed on 15 days after treatment when seeds were treated with either Beaveria
bassiana or Metarhizium anisopliae in combination with diatomaceous earth in all
cereal except on ragi where it was observed on 7 days after treatment when grains
were treated with Metarhizium anisopliae in combination with diatomaceous earth.It
was observed that, after 50 days of treatment there was no significant effect on
germination percentage of different cereals when seeds were treated with Beauveria
bassiana, Metarhizium anisopliae alone or in combination with diatomaceous earth
(DE).